The prime minister today put a new generation of domestic nuclear power stations at the centre of the government's energy review, saying there was now "feverish rethinking" of energy policy around the world.

In a speech to business leaders which was delayed for nearly an hour by Greenpeace protesters climbing to the roof of the CBI conference and unfurling a "Nuclear: Wrong Answer" banner, Tony Blair declared energy policy was now "back on the agenda with a vengeance".

But his talk was delivered in a small adjoining hall after the protest, which saw two activists climb into the rafters of the Business Design Centre in Islington, north London, and drop stickers with anti-nuclear slogans. A Scotland Yard spokesman later confirmed that two men had been arrested.

Mr Blair finally delivered his address to delegates 48 minutes late as they crowded into a nearby room, joking "this is going to be a surreal occasion".

He told his audience of standing business leaders: "The issue back on the agenda with a vengeance is energy policy. Round the world you can sense feverish rethinking.

"Energy prices have risen. Energy supply is under threat. Climate change is producing a sense of urgency."

Mr Blair went on: "I can today announce that we have established a review of the UK's progress against the medium and long-term energy white paper goals.

The energy minister, Malcolm Wicks, will lead the review, with a policy statement on energy expected in the early summer of 2006.

The prime minister added: "It will include specifically the issue of whether we facilitate the development of a new generation of nuclear power stations.

"In Britain, on any basis, we also have the issue of our transition from being self-sufficient in gas supply to being an importer."

Mr Blair made brief mention of this coming winter's gas crunch, saying if it is as cold as the Met Office suggests, "our gas market will be tight", but that domestic users and most business would not be affected.

But he added: "But for big gas users, Ofgem, the National Grid, energy suppliers and the DTI have all been and will be working to make sure business is aware and ready."

The prime minister also sounded confident that ongoing talks in Montreal on a successor agreement to the Kyoto protocol would produce tangible results, saying he "really believed there will be binding protocol to replace Kyoto".

He indicated some of the countries currently not signed up to Kyoto, which include America and Australia as well as developing nations such as India, China and Brazil, could be persuaded to sign up to such a deal, although he did not give details.

Speaking about the protest that delayed Mr Blair's speech, Greenpeace director Stephen Tinday said: "Today Blair is trying to launch a new nuclear age and we are here to stop him. Nuclear power is not the answer to climate change - it's costly, dangerous and a terrorist target. Today's new review is simply a smokescreen for pushing his newfound enthusiasm for nuclear power."

But Mr Blair's official spokesman said: "What we want is a serious debate, not stunts."

John Cridland, deputy director general of the CBI, said the protest was a "disgrace", but added that security would now have to be reviewed.

"The business community is prepared to engage in real debate and I think this has been a disgraceful display by Greenpeace," he said.

Friends of the Earth today called for the review to focus on "clean and safe alternatives to fossil fuels".

But there are also voices within the green movement who see nuclear power - free of emissions of the greenhouse gas carbon dioxide - as a key weapon in the battle against global warming.

And there is support for nuclear among businesses concerned about the UK's reliance on imports of gas from abroad, amid fears of power shortages if the coming winter is as cold as forecast.

Speculation that the prime minister personally backs the nuclear option was heightened earlier this month when his chief scientific adviser, Sir David King, publicly urged him to "give the green light" to the sector.

Sir David has provided Mr Blair with studies of the UK's future energy needs which are certain to have been influential on his thinking. He has warned that the decline in nuclear power was contributing to the failure to meet government targets on reducing CO2 emissions by 2010.

Until recently, nuclear power met almost a quarter of the UK's energy needs, but that figure is set to drop to 4% by 2010 unless new reactors are built.

FoE today said a comprehensive programme of energy efficiency, renewable energy and cleaner use of fossil fuels could allow the UK to meet targets for cutting greenhouse gases, while maintaining fuel security.

Its director, Tony Juniper, said: "The UK can meet its targets for tackling climate change and maintain fuel security by using clean, safe alternatives that are already available.

"But these have so far been underplayed by the prime minister, who has fallen for the nuclear industry's slick PR campaign.

"The government's energy review must cut through this spin, promote the clean, safe measures we know will meet our energy needs, and show that nuclear power is unnecessary - as well as unsafe and uneconomic."

Shadow trade and industry secretary David Willetts said: "To launch an energy review only now is testament to Labour's failure to tackle the problem a long time ago.

"A leak from the DTI in May showed that civil servants were calling on the government to start an energy review, but it has taken them seven months and an energy crisis to get things rolling.

"After the shambles of the Turner report, what are the chances of Gordon Brown agreeing anyway?"

Liberal Democrat environment spokesman Norman Baker said: "The suspicion must be that Tony Blair has already decided to advocate an increase in the use of nuclear power. This review will serve little purpose if the prime minister has already made up his mind.

"What is needed is to rule out an extension of nuclear power now. This will provide the certainty that the industry so desperately needs, and will allow us to focus on cleaner renewable energy."